In wireless networks, some classes of devices may be capable of direct communication with the wireless wide area network (WWAN), but also of lower-power, shorter-range communications with another device. Thus it may be beneficial for edge devices to use hub devices which may act as a proxy or relay to carry traffic between the edge device and the network, while facilitating that the edge device conserving battery power by using only a short-range link.
Also, some devices may lack WWAN capability entirely, or be out of coverage of the cellular network, and capable of contacting a suitable hub device through a device-to-device radio link. In these situations, the ability to relay traffic through the hub device facilitates that the edge device receives service from the network even though it cannot make direct radio contact.
In a network with many edge devices, there may be scaling problems associated with edge devices being independently connecting to the network. Also, the edge devices may have negative battery life effects from maintaining a WWAN connection. Because edge devices may be low powered devices, it is desirable for edge devices to conserve battery power when searching for a hub device.
In third generation partnership (3GPP) systems, the measurement procedures used by connected user equipments (UEs) is based on a framework, where the serving network provides a measurement configuration, which includes an indication of the resources to be measured. The measurement configuration may also provide a reservation of radio resources, for example compressed mode in universal mobile telecommunications systems (UMTS), to facilitate the UE performing searches and measurements towards objects that require retuning of the radio front end. This framework may be problematic for edge and hub devices.
The network may not be aware of the existence of hub devices in its coverage area, and may not be able to enumerate the hub devices as measurement objects in a measurement configuration for an edge device. When a hub device is known to the network, the network is unlikely to know in advance which edge device may be served by that particular hub device. Also, the availability and condition of links between a hub device and an edge device may not be known to the network. The links may use radio resources which were granted by the network for general device-to-device (D2D) use, for example under the proximity services (ProSe) framework. Configurations and radio conditions which are important to the searcher might not be available to the covering wide area network (WAN). The network is poorly positioned to understand the quality of service that the hub device is will offer the edge device. Although the network knows the channel conditions between the communications controller and the hub device, the network is not knowledgeable about the radio frequency (RF) environment between the hub device and the edge device. Low level interference may be negligible at the macro level but important for a low-power D2D link.